The invention discloses an image signal conversion system based on low-pass filtering processing. The image signal conversion system is characterized by mainly consisting of a single chip microcomputer, a signal discriminator, a low-pass filtering processing unit and a time sequence detector that are all connected with the single chip microcomputer, a signal output adjustment unit that is connected with the low-pass filtering processing unit, and an image signal receiver separately connected with the signal discriminator and the time sequence detector. According to the image signal conversion system disclosed by the invention, the signal discriminator can be used for discriminating auxiliary image information loaded in the image signal to ensure that the image signal is more stable; the time sequence detector can be used for judging a signal time sequence of the image signal to determine whether the image signal is a sampling image signal; and the signal is also processed by the low-pass filtering processing unit and the signal output adjustment unit so as to ensure that the problem of signal attenuation of the image signal after analog-to-digital conversion and the enhancement of interference signals in the image signal can be well solved.